Stromfühler für medizinische Apparate mit stetiger Überwachung

摘要

A current sensing device enables sensing the current being delivered from a source 10 to a load ZL at a medical implements, e.g. electrosurgical trocar, connected to the distal end of a primary conductor 14 by compensating for distributed capacitance between the primary conductor and a return path to the source. The current sensing device includes a reference conductor 22 which is located beside and is preferably twisted together with the primary conductor 14 along the length thereof and which is connected to the medical implement load ZL through a resistor R1 of a value such as to effectively electrically isolate the reference conductor from the load. A subtractor 24 subtracts the current flowing through the reference conductor 22 from the total load current flowing to the medical implement so as to offset the effect of the distributed capacitance and to thereby produce a current measurement corresponding to the delivered current The subtractor can comprise a current transformer 24 through which the conductors extend in opposing relation. An Integrity detector 46 monitors whether the reference conductor is intact. <IMAGE>